Network and connected devices for emergency response and roadside operations

ABSTRACT

A self-assembling network is configured to automatically and dynamically connect devices used in operations carried out on or near roads bearing vehicle and pedestrian traffic. An automatic, ad hoc network connecting existing and new devices can be used to enhance safety by gathering and exchanging safety critical information. In some cases, existing equipment can be augmented with a network controller and radio frequency communications to permit the devices to join a wireless local network and exchange information over the network. New devices, including wearable devices, can be configured to act as nodes on the wireless local network. Establishing the relative position of vehicles, sensors, wearables, and other nodes on the disclosed ad hoc wireless network allows the coordination of functions based on position.

BACKGROUND

This application relates to systems, equipment and methods employing aself-assembling wireless local network of devices to enhance the safetyof personnel conducting operations on or near working roadways includinglaw enforcement, emergency response, construction sites, and roadsideservice providers such as tow trucks.

It is well-known that operations conducted on or beside traffic bearingroadways are extremely hazardous, with other motorists potentiallycolliding with equipment and personnel causing injury and death. Visualand audible warnings are commonly used to warn approaching motorists andpedestrians of roadside operations, and these warnings have beensuccessful in reducing accidents. However, significant risks remain andthere is an opportunity to deploy recently developed communications andsensor technology to further increase the safety of roadside personnel.

Currently, equipment used for operations on or near working roads arestand-alone devices, the operation of which is not coordinated withother devices. For example, if two or more emergency vehicles arestopped in a row at the scene of an accident, it is common for all ofthe vehicles to display warning light signals of various types. Thewarning light signals are not coordinated and can generate a confusingglare to the approaching motorist, pedestrian, or other emergencyresponders. It is common for emergency vehicles in the front of the lineto continue projecting warning light signals rearwardly, which can blindemergency responders approaching the accident from behind the firstvehicle. Ideally, only the rear-most vehicle would display warninglights to the rear, to warn approaching traffic. Coordinated trafficdirecting signals would also be less confusing to approaching traffic.Currently, there is no way to effectively coordinate the warning signalactivity among several emergency vehicles at the scene of an accident,except to manually set each vehicle's warning system to the desiredsetting. Even then, the flash patterns emitted by each vehicle's lightswill not be coordinated in time with the other vehicle flash patterns.

Warning signals from emergency vehicles, service vehicles andconstruction equipment can be augmented with traffic guiding devicessuch as cones, portable barriers, and portable lights that generatetraffic guiding light signals or illuminated words. The effectiveness ofsuch equipment is enhanced when the activity of the devices iscoordinated. Further improvements are possible if the traffic guidingdevices include sensors to detect approaching vehicles or objects thatwill enter a safety margin around the work zone. The information fromsuch sensors is most effective if coordinated and communicated topersonnel in the work zone.

It is now common for motor vehicles equipped for road service,construction, and emergency response to have computerized devices thatcontrol and coordinate available audible and visual warning signalsgenerated by each of the vehicles. These computerized devices havecomputer processors, memory, and limited communication capability.Communication is typically limited to the control of signal devices on amotor vehicle from a central module. Some communication between thecentral module and the vehicle communication bus may be employed toobtain information about the status of the vehicle, including whetherthe vehicle is parked or moving, braking, speed, heading, etc.

There is an opportunity to enhance safety of emergency responders,construction crews and road service personnel by connecting devices intoa wireless local network to exchange information and coordinate warningsignal and other activity when responding to an emergency, at crimescenes, emergency response locations, and work zones.

SUMMARY OF THE INVENTION

The disclosure encompasses methods of using networked devices to enhancefirst responder safety, a system of networked programmable devicesprogrammed to carry out the disclosed methods, and devices includingcomputer usable medium having computer readable program code forcarrying out the disclosed methods. Programmable devices may include auser interface allowing a user to receive information from the deviceand input commands to the device, memory for storing program code, aprocessor for executing the code and a communications interface forcommunicating with other devices on the network.

A self-assembling network is configured to automatically and dynamicallyconnect devices used in operations carried out on or near roads bearingvehicle and pedestrian traffic. An automatic, ad hoc network connectingexisting and new devices can be used to enhance safety by gathering andexchanging safety critical information. In some cases, existingequipment can be augmented with a network controller and radio frequencycommunications to permit the devices to join a wireless local networkand exchange information over the network. New devices, includingwearable devices, can be configured to act as nodes on the wirelesslocal network.

According to aspects of the disclosure, emergency vehicles from a firstresponder organization such as a state, county, or city police or firedepartment are provided with wireless communication equipment(transceivers) and configured to automatically join an ad hoc localnetwork when within range of the wireless communication equipment ofother nodes. The vehicles may be nodes on the network and communicationsbetween vehicles over the network may be used to coordinate thefunctionality of warning equipment on the vehicles. Vehicles on thenetwork may also exchange information relating to vehicle position,speed, heading, braking, (generally referred to as “vehicle telematics”)for the purpose of coordinating the functions of warning equipment onthe vehicles based on the relative position of the vehicles. Vehicletelematics transferred between vehicles may also be used to improvefirst responder safety by providing enhanced warning to a trailingvehicle of rapid deceleration of the lead vehicle. Peripheral devicessuch as devices worn on the person of a first responder are wirelesslyconnected to the vehicle and by extension to the network. Portabledevices such as traffic safety cones or barriers are wirelesslyconnected to the network and configured to transfer messages andcommands among connected devices. Portable devices may be equipped withsensors to detect encroachment upon or intrusion into a safety zone atthe scene of an emergency or work zone.

Position detection may be determined by global positioning satellite(GPS) or more accurately by differential global positioning satellite(DGPS) as is known in the art. Position accuracy can be enhanced usingdead reckoning, vehicle telematics, and sensors arranged on thevehicles, wearable devices or portable nodes such as traffic cones orbarriers. Sensors include micro-electro-mechanical (MEM) sensors,accelerometers, gyroscopes, magnetometers, cameras, ultrasonic sensors,infrared or laser radar, and RFID tags. Vehicle navigation systems mayalso provide information that can be used to improve the accuracy ofposition detection. Vehicle navigation systems and related map databasesallow vehicles to detect their position on a roadway and can be used inconjunction with other position sensing methods to determine theposition of vehicles relative to each other. Establishing the relativeposition of vehicles, sensors, wearables, and other nodes on thedisclosed ad hoc wireless network allows the coordination of functionsbased on position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 graphically illustrates the layers in a communication protocolstack and the associated international standards that apply to eachlayer in the stack;

FIG. 2 illustrates an example of a system of devices connected by awireless local network according to aspects of the present disclosure;

FIG. 3 is a functional block diagram of an exemplary controller for adevice in the disclosed system and wireless local network;

FIG. 4 is a graphical presentation of representative traffic directingcones or barriers suitable for use in the disclosed system and wirelesslocal network;

FIG. 5 is a graphical presentation of a representative wearable devicesuitable for use in the disclosed system and wireless local network;

FIG. 6 is a functional block diagram showing a representative vehiclecontrol unit that may interact with the disclosed system and wirelesslocal network; and

FIG. 7 is a block diagram of representative steps in a method ofoperating a system according to aspects of the disclosure.

DETAILED DESCRIPTION

A wireless local network 10 is employed to automatically and dynamicallyconnect vehicles, traffic directing apparatus and wearable devices intoa system 200 to enhance the safety of first responders conductingoperations on or near roadways. One example of a network topologycompatible with the disclosed system 200 and methods is a wireless meshnetwork. A mesh network is a local network topology in which the nodesconnect directly, dynamically, and non-hierarchically to as many othernodes as possible and cooperate with one another to efficiently routedata among the nodes. Mesh networks dynamically self-organize andself-configure, which can reduce installation overhead. The ability toself-configure enables dynamic distribution of workloads, particularlyin the event that a few nodes should fail. This in turn contributes tofault-tolerance and reduced maintenance costs. The disclosed wirelesslocal network is self-configuring and conducts many functions withoutrequiring intervention from personnel using the equipment connected tothe network, allowing them to focus on their work.

Mesh topology may be contrasted with conventional star/tree localnetwork topologies in which devices are directly linked to only a smallsubset of other devices, and the links between the devices arehierarchical. A mesh is a network topology in which each node relaysdata for the network. All mesh nodes cooperate in the distribution ofdata in the network, so devices that are out of range from each othercan communicate though other devices between them. Mesh networks can bedesigned to have no single point of failure. Devices that performspecial functions can be replaced by other devices equipped for thespecial function. There may be some special functions that do not havebackup capability, for example a device that acts as a gateway betweenthe mesh network and the internet. If such a gateway loses power, thenthere may be no way to switch to another gateway.

One example of a protocol for device-to-device communication over awireless local network is the Thread stack, developed by Thread Group,Inc. and is used in this disclosure as a representative standard thatcan be used as the basis for security, communications, and data transferon a mesh network. FIG. 1 is a graphical representation of the layers inthe Thread protocol on the left, with the standards relevant to thecontent and operation of each layer to the right. Radio frequency (RF)communications between nodes on a Thread-based mesh network are governedby IEEE 802.15.4, which defines a Medium Access Control (MAC) layeroperating in the 2.4 GHz band at a data rate of 250 kbps. The MAC layerincludes MAC security for encrypting communications on the mesh networkfor enhanced security,

Thread uses as its RF (Radio Frequency) connectivity protocol the IEEE802.15.4 communication standard which is specifically designed forlow-rate, low-power WPANs (Wireless Personal Area Networks). Threademploys IPv6 connectivity that allows devices to communicate with oneanother, access services in the cloud, or interact with the user throughThread mobile applications. The need to unify IPv6 and 802.15.4technologies was resolved by the development of a layer that providessmooth adaptation between the IPv6 networking layer requirements and802.15.4 link layer capabilities. This layer is called 6LoWPAN and isillustrated FIG. 1.

MAC layer encryption and integrity protection is used on messages basedon keys established and configured by the higher layers of the softwarestack. Nodes are authenticated to the network by authorized personnelusing a device known as a commissioner and must share the same networkkey. A commissioner is usually a device separate from the network, suchas a smartphone, that can communicate with the network and provide thenew device with the necessary security information to join the network.The commissioner device may also be a part of the network itself, oradedicated node.

The wireless local network in this disclosure will be discussed in termsof “nodes,” which is used interchangeably with “device” or “vehicle.”Each node represents one point in a mesh network. FIG. 2 illustrates arepresentative mesh network 10 in which three emergency vehicles 12 areconnected to each other. A representative roadway 14 includes anincident 16 to which the emergency vehicles 12 are responding. Emergencyvehicles 12 may include police, fire, ambulance/EMT and rescue vehicles,as well as DOT, wreckers and tow trucks. Each vehicle 12 includes acontroller 18 with memory 20, a processor 22 and program instructionsstored in memory 20 for execution by the processor 22, as shown ingreater detail in FIG. 3. The controller 18 also includes a presentationinterface 24 to present information to a user, and a user inputinterface 26, for the user to interact with the controller 18. Thecontroller 18 includes a communications interface 28 to managecommunications between the controller and other devices, includingdevices on the disclosed wireless local network 10 via a wirelesstransceiver 30. The controller 18 is operatively connected to an antenna32 for accessing the internet 34 via cellular communications systems asis known in the art. According to aspects of the disclosure, eachvehicle 12 is equipped with a dedicated wireless transceiver 30compatible with a low power, local area network such as a wireless meshnetwork. The controller 18 of each vehicle 12 may be configured todynamically and automatically connect to other vehicles 12 when thewireless transceivers 30 are within range. FIG. 2 illustrates asituation where three vehicles 12 are within range of each other and areall connected to each other in a fully meshed topology to form awireless local network 10. Smart devices, such as cell phones can benodes on the wireless local network 10.

Each vehicle 12 is equipped with at least one multifunction audiowarning device 36 (such as an electronic siren) and at least onemultifunction visual warning device 38 (such as a lightbar). Themultifunction audio device 36 is capable of generating several audiblewarning sounds, such as siren tones known as a wail, yelp, and air horn.The multifunction visual warning device 38 may be a lightbar equippedwith several lights capable of generating a variety of visual warningsignals, which may include flashing lights, steady lights, alternatingwig wag flash patterns, sequential traffic directing patterns, as isknown in the art. The light bar 38 may be configured to generate visualwarning light signals projecting away from the front 38 a and/or rear 38b of the lightbar 38. The lightbar 38 may also capable of selectivelyproducing light to illuminate the area surrounding the vehicle 12, withthe illumination light directed toward the area in front, to the sides,and/or to the rear of the vehicle 12. The three vehicles 12 canimplement a coordinated flash pattern where the pattern incorporates thevisual warning signal devices 38 of all three vehicles 12. When anothervehicle 12 comes within range of the wireless transceivers 30 andautomatically joins the network 10, its visual warning signal device 38may be incorporated into the flash pattern according to programinstructions in the controller 18. Warning lights that would otherwisebe distracting to officers at the scene can be modified or turned off,while traffic directing signals or illumination lights could be turnedon.

The vehicles 12 may also be equipped with at least one sensor 40 forcollecting information regarding the vehicle 12 or the environmentsurrounding the vehicle 12. Sensors 40 include, but are not limited tocameras, radar, ultrasonic or sound based sensors, distance measurementdevices, accelerometers, or the like. Sensors 40 may be selected tosupplement position sensing equipment such as GPS or DGPS to determinethe position of the vehicles 12 relative to each other. One example of asensor is a radar or proximity detecting device arranged at the front ofa vehicle, where the sensor detects the distance between the vehicle andthe vehicle ahead. This information can be used to provide the vehicleoperator with a warning if the distance between the vehicles is suddenlyreduced, indicating a likelihood of collision.

The relative position of nodes (devices) in the disclosed system 200 isused to coordinate the activity of the devices, or nodes on the wirelesslocal network 10. For example, the second (and later) vehicles 12 toarrive at the scene may be configured to extinguish their forward facingwarning light signals in favor of forward facing illumination, toimprove visibility at the scene. The first and second vehicles 12 may beconfigured to extinguish their rear facing warning lights, becauseanother vehicle 12 has joined the group and will maintain rear facingwarning lights to warn oncoming traffic. In this scenario, the first andsecond vehicles 12 could be configured to project an alternative warningsignal pattern, such as a traffic directing (sequential amber lights),or a steady, low intensity pattern on the rear of each lightbar 38.

FIG. 2 also depicts peripheral devices that are nodes on the disclosedwireless local network. An array of traffic directing cones or barriers42 is shown arranged in a row extending from the rear left corner of thelast (rear) vehicle 12. As shown in FIG. 4, each of the cones orbarriers 42 includes a power source 44, a controller 19 including aprocessor 22, memory 20, and a wireless transceiver 30, allowing thecones/barriers 42 to join the self-assembling wireless local network 10.Each of the cones or barriers 42 may also include a visual warningdevice such as a light 46 for generating visual light signals and/or aspeaker or tone generator 48 for generating audible signals. Each of thecones or barriers 42 may also include sensors 40 or other hardware fordetermining the relative position of the barriers 42 relative to theother barriers 42 and relative to the one or more emergency vehicles 12.The functionality of the cones or barriers 42 may be partly determinedby their relative position. For example, the warning lights 46 of eachcone 42 may illuminate in a sequential pattern to guide oncoming trafficaround the scene. The barriers 42 may be connected to each other byinfrared lasers or light beams 50 that allow detection of an objectpassing between the barriers 42. This feature can be used to form a“virtual fence” around the response scene and the barriers 42 may beconfigured to alert first responders at the scene of such an intrusion.One or more of the traffic cones or barriers 42 may also include sensorssuch as radar or laser radar 50 arranged to detect the speed andtrajectory of vehicles approaching the response scene, with the system200 programmed to use information from the radar 50 to calculate thelikelihood of an intrusion and provide a warning to first responders atthe scene of a vehicle likely to enter the scene. Each of the trafficcones 42 may include an RFID tag 54 to authenticate the cone 42 to thesystem 200. An authentication token or code may alternatively beprovided in firmware or hardware on the cone 42 and exchanged with othernodes on the network 10.

FIG. 2 also depicts a further node on the disclosed wireless localnetwork 10 in the form of a wearable device 52 on the person of a firstresponder. As shown in greater detail in FIG. 5, the wearable device 52will include a power source 44, a controller 19 with a processor 22 andmemory 20, and a transceiver 30, allowing the wearable device 52 to jointhe disclosed wireless local network 10. The wearable device 52 mayinclude a haptic device 56 for generating vibrations to alert the firstresponder to dangerous conditions including an intrusion or likelyintrusion of the response scene. The wearable device 52 may includesensors 58 for detecting the condition and orientation of the officer,for example whether the officer is upright and moving or has fallen downand is not moving. The wearable device 52 may detect the vital signs ofthe officer through one or more sensors 58. The wearable device 52 mayinclude an RFID tag 54 or other mechanism for identifying the particularfirst responder wearing the device 52. This responder identification canbe reported to the wireless local network 10 for the purposes oftracking personnel as they join or depart from a scene, and thecondition of those personnel while at the scene. The system 200 andwireless local network 10 may be configured to report and update theidentification of vehicles 12 and personnel at a response scene to oneor more emergency response coordination centers through the internetand/or via a cellular network. The wearable device 52 may includeaudible tone generators 48 and a homing beacon 60 to facilitate locatinga first responder in the dark, dense foliage, steep vertical terrain,smoke, or other environments where it can be difficult to locatepersonnel who are possibly unconscious and unable to move. Signalstrength from the homing beacon 60 may be employed to direct searchefforts in a manner similar to the function of avalanche beacons knownin the art. The wearable device 52 may be programmed to reportactivation of the homing beacon to the wireless local network 10, withthe system 200 configured to pass that information along to responsecoordinators and commanders.

The wearable device 52 and emergency vehicle 12 can be configured todetect the proximity of the wearable device 52 (and thus the officer)relative to the emergency vehicle 12. Connection of the RFID tag 54 withthe vehicle 12 may be used as a proxy for the first responder's presenceat the vehicle 12, since the operative range of an RFID tag isrelatively small. A system 200 incorporating a vehicle 12 and wearabledevice 52 may be programmed to enable certain vehicle functionality onlywhen the first responder is present at the vehicle 12. For example, whenthe wearable device 52 is within a pre-determined distance from thevehicle 12, the vehicle will function normally, but if the wearabledevice 52 leaves the pre-determined distance (or the vehicle 12 movesbeyond the pre-determined distance) the vehicle 12 may be disabled orrestricted to limited speed. Other functions of the vehicle 12 may bedisabled when the wearable device 52 is not present, such as the trunklock and/or any locks securing firearms in the vehicle 12. The wearabledevice 52 can be used to associate a specific officer or officers with aspecific vehicle 12 at the beginning of each shift. The command role ofthe officer may be used to alter the functionality or role of thevehicle 12 as a node on the disclosed wireless local network 10. Forexample, if the officer is in a command role, then the vehicle 12 may beconfigured to assume a lead role in the wireless local network 10 andhave functionality that is different than other vehicles on the network10. The wearable device 52 may also include a hardware or software tokenor other security device, allowing the vehicle occupied by the officerto join adjacent local wireless networks. For example, the commandvehicle of a police department or fire department may be authorized tojoin the adjacent police or fire department wireless network, assumingthe command status of the officer has been verified to the localwireless network 10.

All nodes in the disclosed network have some common characteristics:each node includes a processor 22 for executing program instructions,(which may be referred to as a computer processor), machine readablestorage media (memory) 20 for storage of program instructions, and atransceiver 30 for receiving and transmitting data on the wireless localnetwork 10. For example, in a Thread network, each node in a meshnetwork is assigned a role and that role can change depending upon thenode's location in the network. As used in this disclosure, location inthe network is distinct from the physical location of the device or noderelative to the other devices. Each device may be capable of acting as arouter, where it can forward data from one node to another. One node(device) may be designated as the leader, and handles certain routingand other information on the network. If the leader in the disclosednetwork 10 leaves the network, another device is elected leader.According to aspects of the disclosure, the process of joining andleaving the disclosed mesh network is automatic, requiring no humanintervention. This allows products compatible with the disclosedwireless local network 10 to form “ad hoc” networks when mesh equippeddevices arrive or are deployed at a particular location. The autonomousformation and operation of the disclosed wireless local network 10 andsystem 200 of connected devices free first responders from some routinefunctions while supplementing information exchange, first responder andpublic safety.

According to aspects of the disclosure, the functionality of each devicemay be altered depending upon the physical location of the devicerelative to other devices on the wireless local network 10. Variousimplementations of this concept have been described above with respectto vehicle positions, officer proximity, and devices such as trafficdirecting cones or barriers 42. Position sensing by GPS may not have thespecificity necessary for the system 200 to determine the relativeposition of the vehicles 12 shown in FIG. 2.

Multiple partitions of the same network can exist at the same time. Eachpartition may have its own leader and operate independently of any otherpartitions. Should these partitions come within range of one another,they can merge together seamlessly, and designate a single leader forthe merged network. The design of the wireless local network and theprogram instructions in each node or device will establish rulesregarding joining and leaving the network, as well as when and whetheradjacent networks merge.

Security of a mesh network is best managed within the organizationoperating the network and security information for the network shouldnot be shared outside the organization. So it may not be possible forunrelated networks to automatically merge with each other directly as isthe case with nodes and devices sharing the same network key. Forexample, a network operated by a county Sheriff's department may not beable to directly merge with a network operated by a State PoliceDepartment, because the security key will not be shared between them. Itis possible to establish secure methods of communicating between thedisclosed mesh networks via border routers that act as a gateway to theinternet where data networks are available. Secure communications canalso be established within the network protocol. Examples includesoftware controlled and maintained passwords or tokens. Designatednodes, such as command vehicles, may be allowed to “opt in” tocommunications with other networks.

Reliable communications and data transfer among devices or nodes in awireless local network 10 may require a common time reference forsynchronization. Further, time synchronization on a wireless networkallows for a time division multiple access “TDMA” method to be used overa multi-hop wireless network. One aspect of the disclosedself-assembling network is to wirelessly connect sensors 40, 50, 58deployed on vehicles 12, personnel or traffic directing equipment 42.Each node (device) may include one or more sensors, a computer processor22 with memory 20, signal processing, a wireless transceiver 30 and apower source 44 such as a battery with limited capacity. The nodes mustquickly report the results to a data collection node or access point.Since the nodes are battery-powered, the medium access control (MAC)protocol is helpful in determining network lifetime. Proposed MACprotocols for sensor networks provide either contention based access ortime division multiple access (TDMA). The former, e.g., IEEE 802.11(carrier sense multiple access CSMA), consume more energy than TDMAprotocols because they waste energy in collisions and idle listening.Moreover, they do not give delay guarantees. TDMA protocols are morepower efficient since nodes in the network can enter inactive (sleep)states until their allocated time slots. More recent standards, such asIEEE 802.15.4 allow designers to configure their own timing patterns.With regard to channel access, 802.15.4 uses carrier sense multipleaccess with collision avoidance (CSMA-CA). This multiplexing approachlets multiple users or nodes access the same channel at different timeswithout interference.

Some methods of time synchronization may not be available on a meshnetwork, because of the inability of the MAC layer to time stamp theexact moment when a message was transmitted/received. This leaves theMAC layer delay, or the time between a message being sent and hittingthe air, as completely non-deterministic. One possible method ofcoordinating timing on the disclosed mesh network is receiver-receiversynchronization (RRS), as is known in the art. In an RRS method, a“reference node” sends a message that is commonly witnessed by more thanone receiver at approximately the same time. Receivers then exchangetime stamps of this commonly witnessed event. In this synchronizationmethod, the delay on the transmitter side is irrelevant, becausemultiple receivers detect the message at the same time, establishing acommon time reference. RRS in a mesh network requires three devices, oneto send and at least two to receive, and the three devices must be“fully meshed” to avoid delays associated with multi-hop communications.The term “fully meshed” refers to a situation in which the three networknodes (devices) involved in the RRS method are connected directly toeach of the others.

GPS timing eliminates the need for a minimum of three fully mesheddevices for synchronization. Any number of GPS equipped devices can besynchronized, even without a connection to the disclosed wireless localnetwork 10. Where a GPS signal is available, a GPS receiver can providean accurate time synchronization alternative in the form of a pulse.However, this signal is not always dependable in urban, mountainousterrain or indoor environments. Dedicated GPS timing modules expandtiming capabilities into environments where GPS signal is not available.By using a high accuracy temperature-controlled crystal oscillator(TCXO), devices can maintain an accurate clock pulse for extendedperiods of time after losing GPS signal. In most environments, GPSsignals are interrupted for short periods of time by tunnels, garages,and tall buildings and a GPS timing module can be used to provide thenecessary time reference among nodes on a mesh network.

Modern motor vehicles include advanced electronic systems coordinated byone or more electronic control units. FIG. 6 illustrates arepresentative control unit 62 and associated peripheral equipment,sensors and vehicle systems. The control unit 62 includes memory 63 forstorage of executable computer code, and an accurate clock 65 forcoordination of internal vehicle functions. The vehicle may include aGPS receiver 64, a DGPS receiver 66, inter-vehicle communication 68, andinfrastructure communication 70 for interacting with smartinfrastructure. Vehicle sensors include one or more of accelerometers72, gyroscopes 74, cameras 76, radar 78, laser radar 80, velocity sensor82, weather sensors 84 and stoplight sensors 86. The vehicle includes atleast one display 88 to provide information, and operator controls 90 toprovide inputs to direct vehicle operation. The vehicle may be equippedto generate warning light signals and audible tones 92 perceptible tothe operator within the vehicle, or in the case of an emergency vehicle12, the visual signals and audible tones are perceptible to pedestriansand motorists external to the emergency vehicle 12. Vehicle systems mayinclude a map database 94 for tracking the position of the vehicle on amap that may be displayed to the vehicle operator. Vehicle systemsreceive electrical power 96 from a vehicle electrical system, which istypically a DC system including a battery and engine-driven alternatoras is known in the art. The control unit 62 may communicate with a brakeservo 98, steering servo 100, throttle servo 102 and vehicle diagnostics104. The vehicle may include an RFID 54 or other identifier to providean electronically readable identifier that can be used in electroniccommunications and on networks such as the disclosed wireless localnetwork 10.

Computer code running in the vehicle control unit 62 may be configuredto process data from some or all of the connected systems and devices tocalculate vehicle position and place the vehicle on a map displayed tothe operator. The vehicle control unit 62 can supplement GPS and DGPSinformation with data from vehicle sensors 72, 74, 76, 78, 80, 82 toperform precise positioning calculations and generate warnings to theoperator of dangerous vehicle movements or road conditions. According toaspects of the disclosure, the vehicle control unit 62 may share some ofthe vehicle data, position information, or other data and calculationswith a controller 18 associated with the disclosed wireless localnetwork 10 and connected peripheral equipment 42, 52. Alternatively, thedisclosed system 200 may include its own sensors 40, 50, 58 and performcalculations separately from the vehicle control unit 62. Each node onthe disclosed mesh network can determine its own position using a GPSreceiver a DGPS receiver, or one of these supplemented by sensorfeedback from accelerometers, gyroscopes, radar or signals from othernodes, and broadcast its position to other nodes on the network.

Refinement of GPS is generally known in the art. The accuracy of GPS andDGPS can be improved by a Wide Area Augmentation System (WAAS), a LocalArea Augmentation System (LAAS), or other systems that make use of thecarrier phase. Additional details regarding GPS and DGPS accuracyrefinement are provided by U.S. Pat. No. 6,405,132 to Breed et. al.Precise positioning is possible by refining a GPS location with theaforementioned vehicle telematics, infrastructure-based location aids,Radio-Frequency Identification (“RFID”) tags, cameras, infrared oroptical sensors, radar and laser radar, or other sensors that establishrelative or absolute location.

Each node may be programmed to maintain a database (or other record) ofthe current location of other nodes on the network. This information canbe used to generate a virtual “map” of the relative positions of nodeson the network, which can be used to coordinate node activity. Forexample, warning signals generated by emergency vehicles 12 stopped orarriving at a scene can be coordinated to improve safety. A singlepolice car at a scene should employ its warning lights 38 a, 38 bdirected both forward and to the rear to warn oncoming traffic in bothdirections. However, a second police car arriving at the scene changesthe situation, and coordination between the vehicles 12 would allow therear-facing warning lights 38 b of the lead vehicle to be turned off orchanged to a less dynamic traffic directing pattern, while the forwardfacing lights 38 a of the rear vehicle could be turned off or changed toilluminate the scene.

Such coordination among nodes on a mesh network may require locationaccuracy greater than commonly available using GPS alone, which istypically limited to about 3 meters. Location accuracy can be improvedby accessing vehicle speed and heading information from the vehicle'sinternal communication bus, also referred to as a CAN bus. Otherposition and proximity sensors may be used in tandem with software todetermine the relative position and orientation of other vehicles(nodes) on the network. One scenario where relative position and vehicledirection information may be used to improve safety is in a pursuit orresponse situation where emergency vehicles are following each other.The information could be used to control the warning lights of theleading vehicle, so they do not blind vehicles following close behind.Warning lights could also be configured to warn of sudden braking ordeceleration by a lead vehicle to aid in collision avoidance.

Mesh network capability can be added to existing control modules throughlogic inputs and a network controller. New “scalable” warning signalpatterns can be added to existing libraries of warning light signals.Traffic advisor patterns can be sequenced by activating segments at anassigned time slot according to a synchronized time signal available tothe nodes (in this case emergency vehicles 12 and/or traffic directingdevices 42).

Mesh network connectivity and information transfer can be implementedsuch that the exchange of information and control is a seamless processhandled by the system 200 with little or no human intervention. Networkcapability can be integrated into existing equipment rather than as anadditional add-on system. Nodes are programmed to join and leave thewireless local network 10 according to rules established for thenetwork. The network 10 is configured to be self-assembling andautonomous to a large extent. This frees first responders to do theirjobs, while the connected equipment automatically provides safetyenhancing functionality. One example is a system 200 programmed toperiodically report vehicles 12 and personnel at a particular responsescene. Response coordinators will have accurate and timely informationabout resources at a particular scene, which allows them to assess theneed for additional resources or even to re-direct resources to other,higher priority situations.

Another example is a work zone where a vehicle positioned at thebeginning of the work zone is equipped with sensors that detect thespeed and trajectory of oncoming vehicles. A vehicle that is approachingwith excessive speed or on a trajectory that will enter the work zonetriggers an alert on the disclosed wireless local network 10. In thisscenario, a police officer and workers in the work zone wearing aconnected device 52 configured to receive the alert, are provided withaudible and/or vibratory signals of the anticipated intrusion. Such awarning may provide valuable time for personnel in the work zone to takeevasive action. Additionally, a wearable device 52 could implementmotion sensors such as an accelerometer to detect a situation where aworker or officer falls to the ground. In a law enforcement situation,this event could trigger opening a vehicle door to permit a police dogto assist the officer or trigger a specific pattern of light and/orsirens to draw attention to the scene. Wearable connected devices canalso be configured to report health and status information forpersonnel, such as heart rate and issue alerts when such informationindicates a need for assistance.

The proposed wireless local network 10 could be extended inside astructure by way of portable and wearable nodes, to aid in tracking thelocation of emergency personnel. In this embodiment, the nodes mayinclude waypoints such as a wedge deployed to hold a door open, andwearable devices 52 on personnel moving within the structure. Thisembodiment of the disclosed wireless local network would employ the sameinfrastructure as that described above for the other embodiments, andwould connect sensors, wearable devices and waypoints dynamically.Position sensing may be used to track the location of personnel withinthe structure, including elevation. Wearable devices 52 can monitorconditions such as temperature, compounds in the air, vital signs ofpersonnel, and report this information to situation managers outside ofthe building. Knowing the location of personnel within a structure canaid in assisting personnel in distress, and may be used to directpersonnel how to get out of a dangerous situation.

FIG. 7 illustrates representative steps in a method of operating asystem of devices on a wireless local network according to aspects ofthe disclosure. The devices are configured to automatically join a localwireless network of compatible devices, which include at least oneemergency vehicle, at step 110. The devices transmit data across thenetwork at step 112. The system processes data from the connecteddevices to determine the position of said devices relative to each otherat step 114. The system records the relative positions of the connecteddevices at step 116, and transmits identification of the devices andtheir positions at step 118 to a command center remote from the wirelesslocal network. This transmission of devices and positions at step 118may also include the absolute position, corresponding to the location ona map, of the one or more emergency vehicles included in the wirelesslocal network. The system operates the connected devices according totheir relative position at step 120. Alternative functionality based onposition is described in greater detail above. The system is programmedto periodically repeat steps 112-118 to ensure that informationregarding vehicles and devices at a response scene is accurate asconditions change. Step 120 employs the updated device and positioninformation to alter the operation of devices on the network accordingto the latest device and position information.

What is claimed:
 1. A warning system for multiple emergency vehiclescomprising: a first warning device for an associated emergency vehiclehaving a first plurality of warning functions controlled by a firstcontrol module comprising a first controller and including a firstprocessor which communicates with a first transceiver; a second warningdevice for an associated emergency vehicle having a second plurality ofwarning functions controlled by a second control module comprising asecond controller and including a second processor which communicateswith a second transceiver; wherein the transceivers of the first andsecond warning device function as nodes in a wireless mesh network andsaid processors process data from said transceivers to indicate therelative positions and speeds of said associated emergency vehicles andeach said controller activates a warning function in response to therelative positions and speeds of said associated emergency vehicles. 2.The warning system of claim 1, wherein said warning functions of eachsaid first and second warning devices each include a front facingemergency indicator function and a rear facing emergency indicatorfunction.
 3. The warning system of claim 2, wherein the controller ofsaid first warning device activates a front emergency indicator functionand the controller of the second warning device activates a rear facingemergency indicator function.
 4. The warning system of claim 1, whereina controller of one said warning device activates a collision indicatorwarning function.
 5. The warning system of claim 1, wherein each of saidcontrol modules comprises a security key and further comprising a thirdwarning device for an associated emergency vehicle having a plurality ofwarning functions controlled by a third control module having a securitykey wherein said third device security key is communicated to said firstand second warning devices to allow said third warning device tofunction as a node in a wireless mesh network.
 6. The warning system ofclaim 5, wherein said security key allows police emergency vehicledevices and fire vehicle warning devices to function as nodes in thesame wireless mesh network.
 7. The warning system of claim 1, whereinsaid warning functions comprise two or more signal modules selected fromthe group consisting of warning signal lights, traffic directing lights,collision avoidance indicators, front facing light signals and rearfacing light signals.